McKay's Bunting is one of the rarest and most attractive North American birds. Breeding only on two small, isolated islands in the middle of the Bering Sea, it has not been studied in any detail. During the breeding season, the male McKay's Bunting is the whitest of North American passerines, similar to its closest relative, the Snow Bunting (Plectrophenax nivalis), but with a pure white body and black only on its wing-tips, scapulars, and tail. McKay's Bunting probably evolved from Snow Buntings that became geographically isolated on Hall and St. Matthew islands when sea levels rose at the end of the last ice age. Due to its morphological distinctiveness and geographical isolation, McKay's Bunting is considered to be a separate species from the Snow Bunting.
Because these two species are so closely related taxonomically, we expect that McKay's Bunting will be found to be very similar to the Snow Bunting in most behavioral and ecological characteristics. Only those few details that have been documented explicitly for McKay's Bunting are given in this account.